Droplet information measuring method and apparatus therefor, film pattern forming method, device manufacturing method, droplet discharge apparatus, electro-optical apparatus, and electronic apparatus

ABSTRACT

A droplet information measuring method includes a preparation step of preparing a discharge head for discharging droplets, a measurement step of depositing a plurality of the droplets in series at predetermined intervals, and measuring a drying times of the plurality of droplets, and a calculation step of repeating the measurement step while varying the intervals of the plurality of droplets, and calculating a vapor diffusion distance of the droplets based upon the measurement results.

This is a Division of application Ser. No. 10/885,645 filed Jul. 8,2004, now U.S. Pat. No. 7,438,944. The disclosure of the priorapplication is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a droplet information measuring methodand a apparatus therefor, a film pattern forming method, a devicemanufacturing method, a droplet discharge apparatus, an electro-opticalapparatus, and an electronic apparatus.

Priority is claimed on Japanese Patent Application Nos. 2003-195826,filed Jul. 11, 2003, 2003-195827, filed Jul. 11, 2003, and 2003-195829filed Jul. 11, 2003, the contents of which are incorporated herein byreference.

2. Description of Related Art

The manufacturing process for an electronic apparatus such as anelectro-optical apparatus or a semiconductor device or the like which isused as a display or a display light source or the like, includes stepsof depositing a material upon a substrate, and forming a film upon thissubstrate. The technique for depositing material and the technique forforming a film are intimately related to the quality of the products andto their function, and are very important in the struggle for theenhancement of the performance of the above described apparatuses.

As a technique for depositing material upon a substrate, for example, asdisclosed in Japanese Unexamined Patent Application, First PublicationNo. H11-274671, there is a method of discharging a liquid material asdroplets via a nozzle which is provided to a discharge head. With thisdroplet discharge method, as compared to a technique such as a spincoating method or the like, there are the beneficial aspects that thewaste in the consumption of the liquid material is small, and that it iseasy to perform control of the amount and the position of the liquidmaterial which is deposited upon the substrate.

In techniques for forming a film upon a substrate using a dropletdischarge method, in many cases, a plurality of droplets are depositedupon the substrate in series. In such a case, it may happen that thedrying conditions of a droplet may vary due to the influence of thevapor which escapes from another droplet, and this may lead todeterioration of the quality of the resultant layer.

In addition, with a droplet discharge method, it is easy for theconditions of discharge, such as the amount of discharge of the dropletsfrom the discharge head, to vary according to the characteristics of theliquid material. Due to this, it is desirable to determine the driveconditions of the discharge head appropriately in correspondence to theliquid material which is used, such as for example the lot modificationtime of the liquid material and the like.

Optimization of the drive conditions, for example, may be performed bydepositing a pattern of the liquid material upon the substrate, and bychecking the state of this deposit. That is to say, it is performed byrepeating trials of the above described pattern deposition, whilevarying the drive conditions of the discharge head, until the state ofpattern deposition is as desired. However, this method invites adeterioration of productivity, since it requires a long time period.

In addition, for efficiently planning the optimization of the driveconditions, it is desirable directly to measure droplet information suchas the mass of a droplet which has been discharged from the dischargehead, and to manage the drive conditions based upon the results of thismeasurement. However, since the droplets which are discharged from thedischarge head are very minute, a great deal of time is required forthis measurement, or obtaining a stabilized measurement result may bedifficult.

For example, if the amount of a droplet (its mass or its weight) is tobe measured, there is a method of measuring the weight of a singledroplet by measuring the weight of a large number of droplets (forexample, of 5000 drops) all together, and by dividing the result of thismeasurement by the number of droplets; but, in this method, a lot oftime and of material are required for discharging the droplets for themeasurement. On the other hand, if an attempt is made directly tomeasure the mass of a single drop of liquid by using an accuratemeasuring apparatus, errors can easily arise due to the influence of theviscoelasticity of the droplet.

The present invention has been conceived in consideration of the abovedescribed circumstances, and it takes as its object to propose a methodand a apparatus for measuring droplet information which can be desirablyused when depositing a plurality of droplets in sequence, and inaddition a droplet information apparatus which can measure informationfor the droplets which are discharged from a discharge head in a stablemanner.

In addition, another object of the present invention is to propose afilm pattern forming method, which is capable of striving for theenhancement of film quality.

In addition, another object of the present invention is to propose adevice manufacturing method, an electro-optical apparatus, and anelectronic apparatus, which are capable of enhancing product quality.

SUMMARY OF THE INVENTION

The first aspect of the present invention is a droplet informationmeasuring method having a preparation step of preparing a discharge headfor discharging droplets, a measurement step of depositing a pluralityof the droplets in series at predetermined intervals, and measuring adrying times of the plurality of droplets, and a calculation step ofrepeating the measurement step while varying the intervals of theplurality of droplets, and calculating a vapor diffusion distance of thedroplets based upon the measurement results.

The vapor diffusion distance which is measured by this measuring methodis a quantity which indicates the diameter of the range of the influencewhich the vapor which escapes from one droplet exerts upon anotherdroplet, and it is desirably utilized when depositing a plurality ofdroplets in series, for optimization of the deposition pitch of thedroplets and the like.

In this aspect, it is possible to obtain the drying time of theplurality of droplets based upon, for example, the results of measuringthe masses of the plurality of droplets during the drying process.

In this case, it is possible, for example, to deposit the plurality ofdroplets upon the surface of an electrode which has been provided at anupper portion of an oscillator, and to obtain the masses of theplurality of droplets based upon the results of detection of thefrequency of the oscillator during the drying process of the pluralityof droplets.

According to the above described method, it is possible to measure themass and drying time, even in the case of very minute droplets.

In addition, a film pattern forming method according to the presentinvention include the step of depositing a liquid material as dropletsupon a substrate, and wherein the vapor diffusion distance of thedroplets is measured, and a deposition pitch of the droplets isdetermined, based upon the result of the measurement.

According to this method, it is possible to anticipate enhancement ofthe quality of the film produced, due to optimization of the depositionpitch of the droplets.

By, for example, determining the deposition pitch of the plurality ofdroplets to be long as compared with the vapor diffusion distance, theinfluence of vapor between adjacent droplets is avoided, so that anenhancement of the homogeneity of the film can be anticipated.

In addition by, along with determining the deposition pitch to be shortas compared with the vapor diffusion distance, also depositing the nextdroplet after a droplet which has previously been deposited upon thesubstrate has dried, the influence of vapor between adjacent droplets isavoided, so that an enhancement of the homogeneity of the layer can beanticipated.

In addition, conversely, it will also be acceptable, along withdetermining the deposition pitch to be short as compared with the vapordiffusion distance, also to deposit the next droplet before a dropletwhich has previously been deposited upon the substrate has dried, and tocontrol the drying conditions of the droplet which has previously beendeposited.

In this case, for example, it is possible to keep small the drying speedof the droplet which has previously been deposited, and, as a result, itbecomes possible to control the dried film of this droplet to thedesired form.

Furthermore, with this film pattern forming method, the vapor diffusiondistance can be measured by utilizing the above described dropletinformation measuring method.

In addition, in a device manufacturing method according to the presentinvention, the device may be created by forming a film pattern upon asubstrate, and the film pattern may be formed by the film patternforming method as described above.

According to the method, enhancement of the quality of the devices whichare produced may be anticipated, since a film pattern of high quality isformed.

In addition, a droplet information measuring apparatus for measuringdroplet information related to droplets discharged from a dischargehead, the apparatus having an electrode which is provided so as tooppose the discharge head, an oscillator whose frequency variescorresponding to the mass of an object adhered to a surface of theelectrode, a detection section which detects the frequency of theoscillator before and after the adhesion of the droplet, and acalculation section which calculates the drying time of the droplet,based upon the result of detection by the detection section.

According to the device, the above described droplet informationmeasuring method may be implemented by the above described structure.

In this case, the calculation section may calculate the drying time,based, among the detection results of the detection section, upon thetime period from the time point at which, after the discharge of thedroplet, the frequency has first changed to exceed a predeterminedvalue, until the starting time point for the frequency being in aroughly steady state continuously for longer than a predetermined timeperiod.

In addition, when the droplet information measuring apparatus includesan impedance calculation section having a function of correcting errorsdue to the influence of viscoelasticity of the droplets, the calculationsection may further obtain the drying speed of the droplet based upon,among the detection results of the detection section, the amount ofchange of frequency per unit of time within the time period.

The second aspect of the present invention is a droplet informationmeasuring apparatus for measuring droplet information related todroplets discharged from a discharge head, the apparatus having anelectrode which is provided so as to oppose the discharge head, anoscillator whose frequency varies corresponding to the mass of an objectadhered to a surface of the electrode, a detection section which detectsthe frequency of the oscillator before and after the adhesion of thedroplet, and a calculation section which calculates the mass of thesolid component included within the droplet, based upon, among thedetection results of the detection section, the amount of change of thefrequency between before the adhesion of the droplet, and after thedrying of the droplet.

According to the aspect, the mass of the solid component of the dropletis measured based upon the amount of change of the frequency of theoscillator between before the adhesion of the droplet and after thedrying of the droplet. In this measurement of the mass of the solidcomponent, any influence upon the measurement due to the viscoelasticityof the droplet is avoided, so that a stabilized measurement result isobtained.

In the above described measuring apparatus, the calculation section mayfurther calculate the mass of the droplet which has been discharged fromthe discharge head, based upon the calculation results of the solidcomponent amount of the droplet, and the solid component concentrationof the liquid material. This measurement result does not include anyinfluence of the viscoelasticity of the droplet, and has an accuracywhich is stabilized.

In addition, in the above described measuring apparatus, the calculationsection may calculate the time difference between the time point atwhich the droplet is discharged from the discharge head and the timepoint at which the droplet adheres to the oscillator, and calculates thespeed of flying off of the droplet based upon the time difference andthe distance from the discharge head to the oscillator. By doing this,it is possible to obtain a greater amount of droplet information.

In addition, a droplet discharge apparatus having, a discharge headwhich discharges liquid material as droplets, the above describeddroplet information measuring apparatus, and a control device whichcontrols the drive conditions of the discharge head, based upon dropletinformation measured by the droplet information measuring apparatus.

According to the apparatus, optimization of the drive conditions of thedischarge head is promoted, based upon the results of measurement by theabove described droplet information measuring apparatus. Due to this, itis possible to perform a stabilized droplet discharge at high accuracy.

In the above described droplet discharge apparatus, the control devicemay control the drying conditions of the droplet, based upon dropletinformation which is measured by the droplet information measuringapparatus. By doing this, it becomes possible to control the dryingconditions of the droplet.

In addition, a film pattern forming method includes the step ofdepositing liquid material as droplets upon a substrate, wherein theliquid material is deposited upon the substrate by the droplet dischargeapparatus as described above.

According to the method, since the liquid material is deposited upon thesubstrate in an accurate manner, it is possible to form a film patternat high accuracy in a stabilized manner.

In addition, in a device manufacturing method of the present invention,the device is created by forming a film pattern upon a substrate, andthe film pattern is formed by the film pattern forming method asdescribed above.

According to the method, a reduction of the cost of the device and anenhancement of product quality may be anticipated, since the filmpattern is formed at high accuracy in a stabilized manner.

The third aspect of the present invention is a droplet dischargeapparatus having a discharge head which discharges liquid material froma nozzle as droplets, an oscillator which varies frequency correspondingto the mass of an object adhered to a surface thereof, a detectionsection which detects the frequency of the oscillator before and afteradhesion of the droplet, a calculation section which calculates thesolid component concentration of the droplet adhered to the oscillator,based upon the results of detection by the detection section, and acontrol device which decides upon the drying state of the nozzle, basedupon the calculation results of the calculation section.

According to the aspect, by calculating the solid componentconcentration of the droplet which has been discharged from thedischarge head, it is possible to decide upon the state of drying of thenozzle at a stage before nozzle blocking actually occurs.

For example, by comparing together the solid component concentration ofthe droplet which has been discharged from the discharge head, and theinitial solid component concentration of the liquid material, it ispossible to decide to what extent the liquid material in the nozzle hasdried.

By detecting the state of drying of the nozzle at a stage before nozzleblocking occurs, it becomes possible to prevent nozzle blocking inadvance, so that it becomes possible to prevent the deterioration of theproductivity which accompanies nozzle blocking.

In the above described droplet discharge apparatus, by the controldevice controlling the drive conditions of the discharge head, basedupon the results of calculation of the calculation section, it becomespossible to prevent nozzle blocking in advance.

For example, it becomes possible to prevent nozzle blocking in advanceby, at a stage before nozzle blocking actually occurs, stirring theliquid material in the nozzle via control of the drive conditions of thedischarge head, and by performing the droplet discharge from the nozzleon a preliminary basis.

In addition, the above described droplet discharge apparatus may beapplied to the formation of a pattern of any one of, for example,wiring, a color filter, a photoresist, a micro lens array, aelectroluminescence, and a bio-material.

In addition, the electro-optical apparatus of the present inventionincludes a device which has been manufactured by utilizing the abovedescribed device manufacturing method.

As such a device, for example, it is possible to cite a semiconductorelement, an imaging element, a liquid crystal display element, anorganic electroluminescent element, or the like.

In addition, as an electro-optical apparatus, for example, it ispossible to cite a liquid crystal display apparatus, an organicelectroluminescent display apparatus, a plasma type display apparatus,or the like.

In addition, the electronic apparatus of the present invention includesthe above described electro-optical apparatus.

According to these aspects, efforts are made to reduce the cost and toenhance the quality of the products produced.

Furthermore, the method of manufacturing an electro-optical apparatus ofthe present invention utilizes the above described droplet dischargeapparatus.

In addition, the electro-optical apparatus of the present invention ismanufactured by utilizing the above described method of manufacturing anelectro-optical apparatus.

According to these inventions, efforts are made to reduce the cost andto enhance the quality of the products produced by reliably suppressingnozzle blocking during manufacture and the accompanying deterioration ofproduct quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a figure showing in overall view a droplet informationmeasuring method according to a first embodiment of the presentinvention.

FIG. 2 is a figure showing schematically an example of the structure ofa droplet discharge apparatus according to a first embodiment of thepresent invention.

FIG. 3 is a figure showing the structure of a sensor tip.

FIG. 4 is a figure showing an example of disposition of a sensor tip.

FIG. 5 is a figure showing an example of resonant frequency change of aquartz crystal oscillator.

FIG. 6 is a flow chart showing an example of a procedure for obtainingthe vapor diffusion distance of droplets.

FIG. 7 is a figure showing, for a plurality of conditions (a) to (d) forwhich the distances between a plurality of droplets are different, theresonant frequency changes of a quartz crystal oscillator when thisplurality of droplets have been detected.

FIGS. 8A to 8C are figures showing an example of a procedure of a methodfor forming a linear film pattern upon a substrate.

FIG. 9 is a figure showing another example of procedures of a method forforming a linear film pattern upon a substrate.

FIG. 10 is a figure showing another example of a droplet informationmeasuring apparatus.

FIG. 11 is a figure showing an example of resonant frequency change of aquartz crystal oscillator in the measuring apparatus of FIG. 10.

FIG. 12 is a figure showing another example of resonant frequency changeof a quartz crystal oscillator.

FIG. 13A is a figure showing an example of a drying process for adroplet which corresponds to the change of frequency shown in FIG. 11,and FIG. 13B is a figure showing an example of a drying process for adroplet which corresponds to the change of frequency shown in FIG. 12.

FIG. 14 is a perspective view showing an example of a structure of aliquid crystal display apparatus upon which a color filter which hasbeen manufactured using the droplet discharge apparatus according to thepresent invention has been mounted.

FIG. 15 is a perspective view showing an example of a structure of aportable telephone, which constitutes an example of an electronicapparatus which utilizes a liquid crystal display device.

FIG. 16 is a figure showing schematically an example of the structure ofa droplet discharge apparatus according to a second embodiment of thepresent invention.

FIG. 17 is a figure showing another example of a droplet informationmeasuring apparatus.

FIGS. 18A to 18C are figures showing an example of procedures of amethod for forming a linear film pattern upon a substrate.

FIG. 19 is a flow chart showing an example of processing for preventingblocking of a nozzle in advance.

FIG. 20 is a figure showing an example of a drive signal (a drivewaveform) which is supplied to a piezo element.

DETAILED DESCRIPTION OF THE INVENTION

In the following, the present invention will be explained in detail withreference to the drawings.

First Embodiment

FIG. 1 is a figure showing in overall view a droplet informationmeasuring method according to a first embodiment of the presentinvention.

The droplet information measuring method of the present invention is onein which droplet information which is related to droplets of liquidmaterial which are discharged from a discharge head are measured, and aplurality of droplets are deposited in series upon a predetermined body,and the drying times of this plurality of droplets are measured. Then avapor diffusion distance is obtained by repeating the above describedmeasuring step while varying the interval of the plurality of droplets(the distance between the droplets).

Here, as shown in FIG. 1, “vapor diffusion distance” is obtained as theexternal diameter of the vapor diffusion layer which is created aroundthe droplets. In other words, “vapor diffusion distance” is the combinedlength of the diameter of the droplets and the thickness of the vapordiffusion layer, and it indicates the diameter of the vapor diffusionrange. When the droplets dry, the vapor which comes off into the vaporphase from the liquid phase diffuses three dimensionally in the centersof the droplets. By the vapor diffusion layer is meant the region inwhich a concentration gradient is created in the vapor phase in thevicinity of the droplets, due to the movement by diffusion of moleculeswhich have evaporated from the droplets. Here, in the broad sense of theterm, “vapor diffusion layer” is taken to include a vapor layer which iscreated in the vapor phase in the vicinity of the droplets, and whichhas a concentration which experiences an influence from other droplets.In addition, the distance between the droplets is taken as being theinterval between the centers of two adjacent ones of the droplets.Furthermore, the thickness of the vapor diffusion layer varies accordingto the nature of the liquid material, the concentration of its solidcomponent, the temperature of the environment, and so on.

When a droplet is present within the vapor diffusion layers of anotherdroplet, or when the vapor diffusion layers of two adjacent dropletspartially mutually overlap one another, the speed of evaporation of thedroplet changes, due to change of the vapor concentration at the surfaceof the droplet, and the like. In concrete terms, the shorter is thedistance between the droplets, the greater is the distance by whichtheir vapor diffusion layers overlap one another, and the lower does thespeed of evaporation of the droplets (their drying speed) become, sothat the longer does their drying time become. On the other hand, if thevapor diffusion layers do not overlap one another, the speed ofevaporation of the droplets, and their drying time, almost do not alter,even if the distance between the droplets changes.

Accordingly, it is possible to obtain the vapor diffusion distance ofthe droplets by measuring the drying time of the droplets while varyingthe distance between the droplets. For example, when the distancebetween the droplets is gradually changed, it is possible to obtain thevapor diffusion distance from the transition distance between thedroplets at which the drying time ceases to change in correspondence tochange of the distance between the droplets. This transition distancebetween the droplets is taken as being the vapor diffusion distance. Thevapor diffusion distance of the droplets which has been measured isdesirably used when depositing a plurality of droplets in series, inorder to optimize the deposition pitch of the droplets and so on.Furthermore, the vapor diffusion distance which is measured by thismethod has high utility, since it is obtained based upon an actualphenomenon.

Here, in the above described measurement method, the drying time of thedroplets may be obtained by measuring the masses of the droplets duringthe drying process. In other words, with respect to the passage of time,the masses of the droplets change during drying, and become constantafter drying. Due to this, it is possible to obtain the drying times ofthe droplets by obtaining the periods over which the masses of thedroplet vary. In addition, the masses of the droplets can be measuredaccurately by using an oscillator. A measuring apparatus for the massesof the droplets which uses an oscillator, and a droplet dischargeapparatus which incorporates it, will be explained below.

FIG. 2 is a figure showing an example of the structure of a dropletdischarge apparatus which includes an appropriate measuring apparatusfor implementing the measurement method of the present invention.

In FIG. 2, the droplet discharge apparatus 100 includes a discharge headwhich discharges liquid material in the form of droplets by a dropletdischarge method, a stage 102, a droplet information measuring apparatus150, and a control device 105 which controls these elements dynamically,and the like.

As a technique for discharging by a droplet discharge method, there maybe suggested a static electric control method, a pressure vibrationmethod, an electromechanical conversion method (a piezo method), anelectro-thermal conversion method, an electrostatic induction method, orthe like; and, in the present example, an electromechanical conversionmethod (a piezo method) is employed. Such a piezo method is one whichtakes advantage of the property that a piezo element (a piezoelectricelement) deforms when it receives a pulse type electrical signal, sothat a material which has been stored in a space is subjected by thedeformation of the piezo element to pressure via a flexible element,whereby this material is pressed out from this space and is dischargedfrom a nozzle. Since the droplet discharge by the piezo method does notsubject the material to heat, there is the beneficial aspect that it isdifficult for it to exert any influence upon the composition of thematerial.

The discharge head 101 includes a pressure chamber 110, a piezo element111, and a nozzle 112. Among these, the pressure chamber 110 isconnected to a tank which is not shown in the figure which stores liquidmaterial, and periodically stores liquid material which has beensupplied from the tank. In addition, the piezo element 111 deforms aninner surface of the pressure chamber 110 according to a drive signalwhich is supplied from the control device 105, and increases ordecreases the pressure upon the liquid material within the pressurechamber 110. According to this increase and decrease of the pressure ofthe liquid material due to this piezo element 111, the liquid materialis discharged by the discharge head 101 from the nozzle 112 as droplets.The amount of distortion of the piezo element 111 is controlled byvarying the value of the electrical voltage which is applied to thepiezo element 111. In addition, the speed of distortion of the piezoelement 111 is controlled by varying the frequency of this appliedelectrical voltage. By controlling the drive conditions (the waveform ofthe drive signal) for the piezo element 111, it is possible to controlthe discharge conditions for the droplets by the discharge head 101,such as the amount of material in a single droplet (its mass), the speedat which the droplets are projected, the straightness of projection ofthe droplets, and so on. In addition, the discharge head 101 issupported by a head carriage 108 so as to be freely shiftable in apredetermined direction. This head carriage 108 comprises a drive devicewhich is not shown in the drawings, and, based upon commands from thecontrol device 105, the position of the discharge head 101 is set to apredetermined position.

The stage 102 supports a substrate P for patterning, which is taken asbeing the object body upon which the liquid material is to be deposited,and it comprises a drive device not shown in the figures, and, basedupon commands from the control device 105, it shifts the substrate P ina predetermined direction. It is possible to deposit the liquid materialin a pattern upon the substrate P by repeatedly depositing droplets uponthe substrate P while shifting the discharge head 101 and the substrateP relative to one another. In addition, it is possible to create alinear pattern upon the substrate P by depositing the plurality ofdroplets sequentially in series upon the substrate P when performing theabove described relative shifting.

The measuring apparatus 150 is a device which measures dropletinformation such as the mass and the like of the droplets which aredischarged from the discharge head 101 by taking advantage of thecharacteristics of a piezoelectric element (in this example, a quartzcrystal oscillator 124), and it comprises a pulse generation section120, a sensor tip 121, a frequency counter 122 which serves as adetection section, an impedance calculation section 130, and acalculation section 131 and the like. The pulse generation section 120is a device which supplies a pulse signal to the sensor tip 121, andwhich thereby causes the quartz crystal oscillator 124 to vibrate. Themeasurement of the droplet information is performed in order, forexample, to check that the droplets are being discharged in a desiredstate; and, for example, it is performed before depositing the liquidmaterial from the discharge head 101 upon the substrate P, or whiledepositing the liquid material.

FIG. 3 is a figure showing the structure of the sensor tip 121.

Referring to FIG. 3, the quartz crystal oscillator 124 is apiezoelectric element such as, for example, an “AT cut quartz crystal”oscillator or the like, and a pair of electrodes 125 a and 125 b arefixed to two surfaces thereof so as approximately to oppose one another.In addition, via supports 127 a and 127 b which are endowed withelectrical conductivity, an insulating body 126 supports the quartzcrystal oscillator 124 so that it is free to vibrate. The support 127 a,along with leading to the electrode 125 a, is also connected with aterminal 128 a which is fixed to the insulating body 126. On the otherhand, the support 127 b, along with leading to the electrode 125 b, isalso connected with a terminal 128 b which is fixed to the insulatingbody 126. By the above described structure, the pulse signal which isoutputted from the pulse generation section 120 (refer to FIG. 2) isinputted to the sensor tip 121 via the terminals 128 a and 128 b, andthereby the quartz crystal oscillator 124 vibrates at its resonantfrequency.

FIG. 4 is a figure showing an example of positioning of the sensor tip121 of the measuring apparatus 104.

In FIG. 4, the sensor tip 121 is disposed upon the stage 102 whichsupports the substrate P. In concrete terms, the sensor tip 121 isdisposed upon the surface of the stage 102 upon which the substrate P iscarried at a position which is different from the position at which thesubstrate P is placed, and it can be shifted in the XY plane in thefigure integrally with the substrate P. In addition, with the sensor tip121, the surface of the electrode 125 a is positioned so as to be atroughly the same height as that of the substrate P which has been placedupon the stage 102. With this exemplary arrangement, there is thebeneficial aspect that the difference in the environmental conditionsbetween the sensor tip 121 and the-substrate P is small, so that it ispossible to take advantage of the measurement result using the sensortip 121 in an effective manner during actual processing.

Returning to FIG. 2, one of the electrodes 125 which is provided to thesensor tip 121 is provided so as to oppose the droplet discharge surfacein the discharge head 101. When a droplet which has been discharged fromthe discharge head 101 adheres to the electrode 125 a, the mass of thedroplet which has thus adhered to the electrode 125 a is calculated bythe measuring apparatus 150. Furthermore, when this measurement takesplace, the head carriage 108 shifts the discharge head 101 so that thedroplet adheres to the surface of the electrode 125 a.

The quartz crystal oscillator 124 vibrates at a constant resonantfrequency if the external force which acts upon it is constant, but itis endowed with the characteristic that, when an object adheres to thesurface of the electrode 125 a and the external force changes, itsresonant frequency changes according to the amount of this change. Inother words, the quartz crystal oscillator 124 is endowed with thecharacteristic that, when an object adheres to its electrode 125 a, itvibrates at a resonant frequency which corresponds to the mass of thisobject. In addition, if the object which has adhered is endowed withviscoelasticity, the resonant frequency of the quartz crystal oscillator124 varies according to the viscosity of that object. The measuringapparatus 150 of this example is endowed with a function of correctingerrors due to the influence of the viscoelasticity of the object whichis measured, in other words, is an external scan type device, and it isone which obtains the mass and the viscosity of the droplets.Furthermore, it is possible to obtain the electrical impedance of thequartz crystal oscillator 124 in relation to the frequency from therelationship between the electrical voltage which is applied to thequartz crystal oscillator 124 and the current therein.

This impedance changes greatly in the vicinity of the resonantfrequency. The frequency when the resistance component of the impedancebecomes a minimum is the resonant frequency, and this resistancecomponent becomes the value of the resonant resistance.

The impedance calculation section 130 obtains the value of the resonantresistance of the quartz crystal oscillator 124 by calculation, andsupplies a signal which indicates this resonant resistance value to thecalculation section 131. In addition, the frequency counter 122 detectsthe resonant frequency of the quartz crystal oscillator 124, andsupplies a signal which indicates the result of this detection to thecalculation section 131. The calculation section 131 takes in the signalindicating the value of the resonant resistance which has been outputtedfrom the impedance calculation section 130, and the signal whichindicates the resonant frequency which has been outputted from thefrequency counter 122, and, using these, calculates the viscosity andthe mass of the droplet in the following manner.

Taking the value of the resonant resistance as R, when the viscosity ofthe droplet which has adhered to the electrode 125 a is taken as η, thenthe relationship between these is given by the following Equation:

$\begin{matrix}{R = {\frac{A}{K^{2}}\left( {2 \times \pi \times F \times \;\rho_{L} \times \eta} \right)^{\frac{1}{2}}}} & {< {{Equation}\mspace{20mu} 1} >}\end{matrix}$

Here, K is an electromechanical coupling constant for the piezoelectricmaterial or the magnetostrictive material which indicates the degree ofcoupling between its electrical system and its mechanical system, “A” isthe basic frequency of the quartz oscillator 124, and ρ_(L) is thedensity of the droplet (ink).

In addition, if the amount of change of the resonant frequency beforeand after the adhesion of the droplet is Δfreq, then the relationshipbetween this amount of change Δfreq and the viscosity η is given by thefollowing Equation:

$\begin{matrix}{{\Delta\;{freq}} = {{- F^{\frac{3}{2}}} \times \left( \frac{\rho_{L} \times \eta}{\pi \times \rho_{Q} \times \mu} \right)^{\frac{1}{2}}}} & {< {{Equation}\mspace{20mu} 2} >}\end{matrix}$

Here, ρQ is the density of the quartz crystal oscillator 124, while μ isthe modulus of elasticity of the quartz crystal oscillator 124.

On the other hand, if the mass of the droplet which has adhered to theelectrode 125 a is taken as being Im, then the relationship between thismass Im and the amount of change Δfreq of the resonant frequency isgiven by the following Equation:

${Im} = \frac{{- \Delta}\;{freq} \times A \times \sqrt{\mu_{Q} \times \rho_{Q}}}{2 \times F \times F}$

Here, μQ is the AT cut quartz crystal oscillator constant.

The resonant resistance value changes according to the viscosity η ofthe droplet (refer to equation 1), while on the other hand the amount ofchange Δfreq of the resonant frequency changes according to both theviscosity η of the droplet and its mass Im (refer to Equations 2 and 3).Accordingly, in the calculation section 131, first, the viscosity η ofthe droplet is obtained by substituting the resonant resistance valuewhich has been supplied from the impedance calculation section 130 intoEquation 1.

Next, the calculation section 131 calculates the amount of change Δfreqof the resonant frequency of the quartz crystal oscillator 124 beforeand after adhesion of the droplet by using the resonant frequency whichis supplied from the frequency counter 122, and obtains the mass Im ofthe droplet by calculating Equation 2 and Equation 3, using the amountof change Δfreq and the viscosity η.

Furthermore, when the calculation section 131 obtains the viscosity ηand the mass Im of the droplet, it supplies droplet informationspecifying these values to the control device 105.

FIG. 5 is a figure showing an example of resonant frequency change ofthe quartz crystal oscillator 124 of the measuring apparatus 150 of thisexample. The resonant frequency shown in FIG. 5 is one which takes intoaccount the influence due to the viscoelasticity of the droplet.

In FIG. 5, the time <T11> is the time at which the droplet has beendischarged from the discharge head 101, the time <T12> is the time atwhich the droplet has adhered to the sensor tip 121 (to its electrode125 a), and the time <T13> is the time at which the droplet has finisheddrying. Among these, the discharge time <T11> of the droplet is obtainedfrom the drive signal which is supplied to the discharge head 101. Inaddition, it is possible to obtain the adhesion time <T12> by detectingthe time point at which, after the discharge of the droplet, thefrequency first has changed to exceed a predetermined value. The amountof change of the frequency which is to be the decision standard foradhesion is appropriately determined according to the intended dischargeamount of material in the droplet, and according to the nature of theliquid material which is being used, and the like.

In addition, during the drying of the droplet, the frequency changesaccording to the change of mass of the droplet due to evaporation of itsliquid component (its solvent or its dispersion medium or the like). Yetfurther, since, after the droplet has dried, its mass ceases to changebecause its liquid component has totally evaporated, accordingly thefrequency attains a roughly steady state with respect to lapse of time.Accordingly, after discharge of the droplet, it is possible to obtainthe time <T13> at which this droplet finishes drying, by detecting thestarting time point of a roughly steady state of the frequency whichcontinues for more than a predetermined time period. The continuationtime period for the roughly steady state which is to be the standard forthis detection is suitably determined according to the characteristicsof the measuring apparatus 150, and according to the measurementaccuracy which is required.

It is possible to calculate the mass of the droplet upon its adhesion(the discharge amount) from, among the results of frequency detection,the difference <fa−fc> between the frequency <fa> before adhesion of thedroplet, and the frequency <fc> at the time of adhesion of the droplet(at the adhesion time <T12>). In other words, it is possible to obtainthe mass of the droplet by substituting the above described differencein frequency <fa−fc> in the Equations as the amount of change offrequency Δfreq. In addition, in the same manner, it is possible tocalculate the mass of the droplet at a predetermined time point duringdrying thereof from the difference <fa−fd> between the frequency <fa>before adhesion of the droplet and the frequency <fd> at thepredetermined time point (for example, at the time <Ta>). Thiscalculation is performed by the calculation section 131 (refer to FIG.2).

Here, the time period from the adhesion time <T12> to the time ofcompletion of drying <T13> is the time which is required for the dropletto dry (the drying time). In addition, the amount of change <fb−fc> ofthe frequency in this time interval <T12−T13> is in correspondence tothe change of mass of the droplet during the drying process.Accordingly, it is possible to determine the average speed of dryingwithin the drying time period, based upon the amount of change offrequency <fb−fc> per unit time period in the time period <t12−t13>. Inother words, if the average drying speed is termed Va, then this isgiven by Va=|fb−fc|/|T12−T13|. In addition, by calculating the slope ofthe graph which shows the change of frequency at any given time (forexample, at the time <Ta>) within the drying time period, it is possibleto obtain the drying speed of the droplets at that time.

Next, the method of determining the vapor diffusion distance of thedroplets by using the above described droplet discharge apparatus 100will be explained.

FIG. 6 is a flow chart showing an example of a procedure for obtainingthe vapor diffusion distance of the droplets.

First, the droplet discharge apparatus 100 discharges droplets from itsdischarge head 101 (refer to FIG. 2 ), and (in a step 201) deposits aplurality of droplets (in the shown example, two drops) at apredetermined interval upon the sensor tip 121 (the electrode 125 a).This droplet deposition is performed by relatively shifting thedischarge head 101 with respect to the sensor tip 121.

When this plurality of droplets are deposited upon the sensor tip 121,the measuring apparatus 150 measures (in a step 202) the drying time forthis plurality of droplets. This measurement of the drying time isperformed based upon the result of detection of the frequency of thequartz crystal oscillator 124 before and after the adhesion of theplurality of droplets, as described previously. Furthermore thismeasurement result is stored in a predetermined storage section incorrespondence to data related to the distance between the droplets. Andthe above described deposition of droplets and the above describedmeasurement of the drying time are repeated for a predetermined numberof times (in steps 203 and 204), while the deposition interval of thedroplets (i.e. the distance between the droplets) is varied by thedroplet discharge apparatus.

Next, the measuring apparatus 150 calculates (in a step 205) the vapordiffusion distance of the droplets, based upon the measured data for thedrying time of the plurality of droplets for the various distancesbetween the droplets. Here, FIG. 7 shows, for a plurality of conditions(a) to (d) for which the distances between a plurality of droplets aredifferent, the resonant frequency changes of the quartz crystaloscillator 124 when this plurality of droplets have been detected.

As shown in FIG. 7, among the conditions (a) to (d), (a) is the one forwhich the distance between the droplets is the shortest, while thedistance between the droplets becomes longer in order for (b), (c), and(d). The drying time for each of the conditions (a) to (d) is obtainedfrom the behavior of the change in the resonant frequency as describedpreviously, and it is the longest for (a), while it is the next longestfor (b). In addition, the drying times for (c) and for (d) are almostthe same, and are longer as compared to (b). At this time, it ispossible to obtain the vapor diffusion distance from the distancebetween the droplets of the condition (c), which is the transition atwhich the drying time ceases to change with respect to change of thedistance between the droplets. In other words, in this example, thedistance between the droplets in the condition (c) is determined asbeing the vapor diffusion distance.

Furthermore, since there is a possibility that, in practice, the abovedescribed transition of change of the drying time may be between theconditions (b) and (c), it is possible to obtain a more exact vapordiffusion distance by investigating the drying time again for a distancebetween the droplets which is close to those conditions (b) and (c). Inaddition although, here, in order to determine the vapor diffusiondistance, the drying times from the adhesion time of the droplets to thetime of the completion of their drying are compared, this procedure isnot limitative. For example, it would also be acceptable to obtain thevapor diffusion distance by comparing the times from the adhesion timeof the droplets to when the amount of change of the frequency arrived ata predetermined proportion (for example, 20%).

FIGS. 8A to 8C show, as one example of a film pattern forming method, anexample of a procedure of a method for forming a linear film patternupon a substrate, using the above described droplet discharge apparatus100.

With this film pattern forming method, the liquid material is made intodroplets which are discharged from the droplet discharge head 101, andthese droplets are deposited upon the substrate P with a fixed distance(pitch) between them. Then, a linear film pattern is formed upon thesubstrate P by repeating this action of deposition of droplets.

In concrete terms, first, as shown in FIG. 8A, droplets L1 which havebeen discharged from the droplet discharge head 101 are deposited uponthe substrate P in order with a fixed interval being allowed betweenthem.

In this example, the deposition pitch P1 of the droplets is determinedso that the vapor diffusion layers of each two adjacent droplets do notmutually overlap with one another. In other words, before depositing theliquid material from the discharge head 101 upon the substrate P, thevapor diffusion distance of droplets which are made from the same amountof the same material as the droplets which are to be deposited upon thesubstrate P is measured by the measuring apparatus 150. Then, thedeposition pitch P1 (the distance between the droplets) is set to adistance which is longer, as compared with the vapor diffusion distance.

After having deposited the droplets L1 upon the substrate P, a dryingprocedure is performed, according to requirements, in order to performelimination of the liquid component (the solvent or the dispersionmedium or the like). With regard to this drying procedure, apart fromemploying a conventional type of heating procedure using a heatingdevice such as, for example, a hot plate, an electric oven, a hot airblower, a lamp anneal or the like, it may be performed by shifting thestage upon which the substrate P is carried.

Next, as shown in FIG. 8B, the action of deposition of dropletsdescribed above is repeated. In other words, just as the previous timeshown in FIG. 8A, liquid material is made into droplets L2 which aredischarged from the discharge head 101, and these droplets L2 aredeposited upon the substrate P at a fixed distance apart from oneanother. At this time, the amount of material in the droplets L2 (theamount of liquid material per one droplet) and the deposition pitch P2thereof are the same as for the droplets L1 the time before. Inaddition, the positions of deposition of the droplets L2 are shifted byjust a predetermined distance S1 from those of the droplets L1 the timebefore. In other words, the positional relationship between thepositions of the centers of the droplets L1 the time before which havebeen deposited upon the substrate P and the positions of the centers ofthe droplets L2 this time is that they are separated by just the abovedescribed distance S1. This shift amount S1 is, in this example,narrower than the above described pitch P1, P2 (S1<P1=P2), and moreoveris set so that the droplets L2 the next time partly overlap the dropletsL1 which were previously deposited upon the substrate P.

In addition, at this time, although the droplet L2 this time and thedroplet L1 the time before are in contact, since the liquid component isalready completely or to some extent eliminated from the droplet L1 thetime before, accordingly both the droplets almost do not combinetogether and spread out over the substrate P at all. After the dropletL2 has been deposited upon the substrate P, according to requirements,in order to eliminate the liquid component, a drying procedure isperformed, in the same way as the previous time.

After this, as shown in FIG. 8C, the operation of depositing thedroplets described above is repeated a plurality of times. Each time,the distance interval between the droplets Ln which are deposited (theirpitch Pn) is always fixed as being the same as the distance the firsttime (i.e. the pitch Pn=P1). In addition, when repeating the action ofdepositing the droplets a plurality of times, each time, the initialposition for depositing a droplet Ln is shifted by just a predetermineddistance from the position at which the droplet was deposited the timebefore. By thus repeating the action of depositing the droplets, thegaps between the droplets which have been deposited upon the substrate Pare filled in, and a continuous linear pattern is formed. In addition,the film pattern which is thus formed upon the substrate is formed bydepositing the droplets always at the same pitch, and so the structurebecomes homogenous, since all of it experiences almost the sameformation processing.

With the film pattern formation of this example, the deposition pitchesP1 and P2 of the droplets are long as compared with the vapor diffusiondistance, and, since the vapor diffusion layers of neighboring dropletsdo not mutually overlap with one another, accordingly the influence ofvapor between neighboring ones of the droplets is avoided, so that itmay be expected that the homogeneity of the layer will be enhanced. Inaddition, even if the distance between the droplets L1 which aredeposited first upon the substrate P and the droplets L2 which aredeposited afterwards is short as compared with the vapor diffusiondistance, by depositing the next droplets L2 after the droplets L1 whichhave been previously deposited have dried, it is possible to avoid anythe influence of vapor between adjacent ones of the droplets. Due tothis, the desired dry film is formed for each of the droplets which aredeposited upon the substrate, so that it is possible to form a filmpattern stably at high accuracy.

Furthermore, the method of formation of a linear pattern is not limitedto the one shown in FIG. 8A to FIG. 8C. For example, it would bepossible to set the deposition pitch of the droplets, or the shiftamount for repetition, or the like, as desired.

FIG. 9 is a figure showing another example of procedures of a filmpattern forming method, and is a case in which the deposition pitch P3of the droplets is determined as being short as compared with the vapordiffusion distance. In addition, before the droplets L3 which have beenpreviously deposited upon the substrate P dry, the next droplets L3 aredeposited.

With this film pattern forming method, the drying speed of the dropletsis kept low, since the vapor diffusion layers of adjacent ones of thedroplets mutually overlap with one another. By controlling the dryingspeed of the droplets in this manner, it becomes possible to control thedry film of droplets to the desired form. In particular, in thisexample, the evaporation at the edges of the droplets is restrained,since the drying speed is controlled by the vapor of the droplets whichare deposited upon the same substrate, so that there is an advantage incontrolling the shape of the dried layer.

FIG. 10 is a figure showing another example of a droplet informationmeasuring apparatus (the measuring apparatus 104), and FIG. 11 is afigure showing an example of resonant frequency change of a quartzcrystal oscillator which is detected by the measuring apparatus 104.Furthermore, with regard to the structural elements of the measuringapparatus 104, to elements which are endowed with the same function asones in the measuring apparatus which was previously shown in FIG. 2 andFIG. 3, the same reference symbols are appended, and the explanationthereof will be omitted or simplified.

The measuring apparatus 104 shown in FIG. 10 includes a pulse generationsection 120, a sensor tip 121, a frequency counter 122, a calculationsection 123, and the like. The calculation section 123 inputs a signalwhich indicates the resonant frequency which is outputted from thefrequency counter 122, and obtains the mass of the droplets by usingthis. The measuring apparatus 104 of this example differs from theprevious measuring apparatus 150 in that it has no function ofcorrecting the influence of viscoelasticity of the object ofmeasurement, in other words, it is a self-excited type device. In thefollowing, the method of calculation of the drying time by thismeasuring apparatus 104 will be explained.

In FIG. 11, the time <T1> is the time at which a droplet is dischargedfrom the discharge head 101, <T2> is the time at which the dropletadheres to the sensor tip 121 (the electrode 125 a), and <T3> is thetime at which the droplet has finished drying. Among these, thedischarge time <T1> of the droplet is obtained from the drive signalwhich is supplied to the discharge head 101. In addition, when thedroplet adheres to the sensor tip 121, the frequency changes greatly dueto the energy of the droplet when it impacts. Accordingly, it ispossible to obtain the time at which the droplet has adhered to thesensor tip 121 by detecting the time point at which the frequency hasinitially changed after the discharge of the droplet to exceed apredetermined value. The amount of change of the frequency which is tobecome the decision standard is suitably determined according to thedroplet discharge amount which is the target, the nature of the liquidmaterial which is used, and so on.

In addition, with the measuring apparatus 104 of this example, due tothe influence of the viscoelasticity of the droplet, while the mass ofthe solid component which has been deposited from the droplet isdetected, the mass of the liquid component is difficult to detect. Dueto this, during the drying of the droplet, the frequency changesaccording to the change of mass which accompanies the deposition of thesolid component.

Since, after the drying of the droplet, the solid component is allsolidified and there is no change of the mass, the frequency which isdetected goes into a roughly steady state with lapse of time.Accordingly, after discharge of the droplet, it is possible to obtainthe time <T3> that this droplet finishes drying by detecting the initialtime point that the frequency continues in a roughly steady state formore than a predetermined time period. Then, the time period from theadhesion time <T1> to the time <T3> of termination of drying is the timeperiod required for the drying of the droplet (the drying time).

FIG. 12 is a figure showing another example of resonant frequency changeof a quartz crystal oscillator which is detected by the measuringapparatus 104. Furthermore, in FIG. 12, the drying process for thedroplet which is the subject of measurement is different from the casein the previous FIG. 11.

Here, FIG. 13A is a figure showing an example of a drying process for adroplet which corresponds to the change of frequency shown in FIG. 11,and FIG. 13B is a figure showing an example of a drying process for adroplet which corresponds to the change of frequency shown in FIG. 12.

The drying process for the droplet shown in FIG. 13A is one in which thedrying conditions are determined so that the solid componentconcentration at the edge of the droplet quickly reaches the saturationconcentration, as compared with its central portion. Generally, with adroplet which has been deposited upon a body, the progress of the dryingis quicker at its edge. In the drying process of a droplet, when thesolid component concentration at the edge of the droplet arrives at thesaturation concentration, the solid component locally solidifies at thisedge. Then, due to this solid component which has solidified, the edgeof the droplet comes to be in a state as though it has been pinned down,so that, as the droplet continues to dry further, its contraction (thecontraction of its external diameter) is suppressed. In the following,this phenomenon, in other words the phenomenon that contraction of thedroplet along with further drying is suppressed due to the solidcomponent which has been deposited at its edge, will be termed“pinning”.

On the other hand, the droplet drying process shown in FIG. 13B is onein which the drying conditions are determined so that the saturationconcentration arrives at the solid component concentration all over thedroplet at roughly the same time. In this case the above describedpinning does not take place, since it is difficult for solidification ofa local solid component to take place at the edge of the droplet, and,during the drying process, the droplet contracts along with theevaporation of its liquid component (its solvent or dispersion medium orthe like). In other words, the exterior diameter of the droplet becomessmaller along with the progress of the drying. In the contractionprocess of the droplet, within the droplet, convection which includes acurrent of liquid from the central portion towards the edge and acurrent from the edge toward the central portion is continuouslycreated, and accordingly it may be anticipated that, along with anylocal increase of the solid component concentration within the dropletbeing suppressed, also the solid component concentration will be mademore uniform within the droplet. Then, by the solid componentconcentration arriving at the saturation concentration all over thedroplet, deposition of the solid component takes place almostsimultaneously all over the droplet. In the following this phenomenon,in other words the phenomenon of contraction of the droplet duringdrying without any pinning taking place, will be termed “depinning”.Furthermore, the currents of liquid within the droplet which are shownby arrow signs in FIG. 13A and FIG. 13B are only exemplary, and they maybe different in practice.

Returning to FIG. 12, for the frequency change which corresponds todepinning, the time <T5> is the time at which a droplet is dischargedfrom the discharge head 101, while <T6> is the time at which thisdroplet has adhered to the sensor tip 121 (the electrode 125 a), and<T7> is the time at which this droplet has completed drying. Thedischarge time <T5> of the droplet from the discharge head 101 isobtained from the drive signal which is supplied to the discharge head101, in the same manner as described above. In addition, the adhesiontime <T6> of the droplet may be obtained by detecting the time point,after discharge of the droplet, at which the frequency initially haschanged to exceed a predetermined value.

In the drying process of the droplet with depinning, since almost nodeposition of the solid component takes place during the period untilthe solid component concentration all over the droplet arrives at thesaturation concentration, accordingly it is easy for the frequency whichis detected to become in a roughly steady state (T6 to T7). Then, theabove described solid component concentration reaches the saturationconcentration at the time <T7> that the drying is completed, and thefrequency greatly changes in accompaniment with the solid componentbeing deposited over the entire extent of the droplet at the same time.After this, along with the solid component solidifying and the variationof the mass ceasing, the frequency comes to be in a roughly steady statealong with the passage of time. Accordingly by detecting, after thedischarge of the droplet, the initial time point that the resonantfrequency continues to be in a roughly steady state for greater than apredetermined time period, it is possible to obtain this time <T7> thatthe droplet finishes drying. Then, the time period which is required forthe droplet to dry from the adhesion time <T6> to the time <T7> that thedrying is completed is the drying time. Furthermore, the time period forcontinuation in the roughly steady state which is taken as the standardwhen obtaining the drying completed time <T7> is set so that, duringdrying of the droplet, the frequency exceeds the time period <T6 to T7>which constitutes the roughly steady state.

FIG. 14 is a perspective view showing an example of a structure of aliquid crystal display apparatus upon which a color filter which hasbeen manufactured using the droplet discharge apparatus according to thepresent invention has been mounted.

With the liquid crystal display apparatus according to this embodiment,peripheral elements such as a liquid crystal drive IC (not shown in thefigures), lead wires or the like (not shown in the figures), a lightsource 470, a support (not shown in the figures), and the like areprovided.

The structure of the liquid crystal display device 400 will be simplydescribed. This liquid crystal display device 400 principally comprisesa color filter 460 and a glass substrate 414 which are arranged so asmutually to oppose one another, a liquid crystal layer not shown in thefigure which is sandwiched between these two elements, a lightpolarizing plate 416 which is attached to the upper surface side of thecolor filter 460 (i.e., to the side of the observer), and a lightpolarizing plate not shown in the figures which is attached to the lowersurface side of the glass substrate 414. The color filter 460 isequipped with a substrate 461 which is made from transparent glass, andwhich is a substrate provided upon the side of the observer, while theglass substrate 414 is a transparent substrate which is provided to theother side thereof.

On the lower side of the substrate 461, there are formed, in order, adivision wall 462 which is made from a black colored light sensitiveresin layer, a colored portion 463, and a overcoat layer 464; inaddition, an electrode 418 for driving is formed on the lower side ofthe overcoat layer 464. Furthermore, in an actual liquid crystal device,there are provided a liquid crystal layer side which covers theelectrode 418, and an orientation layer over an electrode 432 which willbe described hereinafter on the side of the glass substrate 414, butthese will be omitted from the drawings, and from this explanation.

The electrode 418 for driving the liquid crystal which is formed uponthe liquid crystal layer side of the color filter 460 is one which ismade from a transparent and electrically conductive material such as ITO(Indium Tin Oxide) or the like, and which extends all over the surfaceof the overcoat layer 464.

An insulating layer 425 is formed over the glass substrate 414, and,over this insulating layer 425, there are formed TFTs (Thin FilmTransistors) which serve as switching elements, and picture elementelectrodes 432.

Over the insulating layer 425 which is formed over the glass substrate414, there are provided scanning lines 451 and signal lines 452 in amatrix form, and the picture element electrodes 432 are provided in eachof the regions which are surrounded by the scanning lines 451 and thesignal lines 452. The TFTs are fitted at the portions between the cornerportions of each of the picture element electrodes 432 and the scanninglines 451 and the signal lines 452, and the supply of current to thepicture element electrodes 432 is controlled by signals being appliedthrough the scanning lines 451 and the signal lines 452 so as to turnthese TFTs into the ON state or the OFF state.

FIG. 15 is a perspective view showing an example of a structure of aportable telephone, which constitutes an example of an electronic devicewhich utilizes the above described liquid crystal display apparatus. Inthis figure, the portable telephone 92 includes the above describedliquid crystal display apparatus 400, as well as a plurality ofoperating buttons 921 and a speech reception aperture 922 and a speechtransmission aperture 923.

Second Embodiment

FIG. 16 is a figure showing schematically an example of the structure ofa droplet discharge apparatus according to a second embodiment of thepresent invention.

In FIG. 16, the droplet discharge apparatus 200 comprises a dischargehead 201 which discharges liquid material in the form of droplets by adroplet discharge method, a stage 202, a droplet measuring apparatus204, a control device 205 which controls these elements dynamically, andthe like.

As the discharge technique for this droplet discharge method, there maybe proposed a static electric control method, a pressurization vibrationmethod, an electromechanical conversion method (a piezo method), anelectro-thermal conversion method, a static electric aspiration method,or the like; and, in the present example, an electromechanicalconversion method (a piezo method) is employed. In such a piezo method,by taking advantage of the characteristic that a piezo element (apiezoelectric element) deforms when it receives a pulsed electricalsignal, pressure is applied via a flexible object to a space in which amaterial is stored by deforming a piezo element, and the material ispressed out from this space and is discharged from a nozzle. Since suchdroplet discharge by a piezo method does not apply heat to the material,accordingly it is endowed with the beneficial aspect that it isdifficult for it to exert any influence upon the composition of thematerial.

The discharge head 201 includes a pressure chamber 210, a piezo element211, and a nozzle 212. Among these, the pressure chamber 210 isconnected to a tank not shown in the figures which stores liquidmaterial, and temporarily stores liquid material which has been suppliedfrom the tank. In addition, the piezo element 211 causes the innersurface of the pressure chamber 210 to deform according to a drivesignal which is supplied from the control device 205, and increases anddecreases the pressure upon the liquid material which is within thepressure chamber 210. According to this increase and decrease ofpressure of the liquid material caused by the piezo element 211, theliquid material is discharged as droplets by-the discharge head 201. Theamount of distortion of the piezo element 211 is controlled by varyingthe value of the electrical voltage which is applied to the piezoelement 211. In addition, the speed of the distortion of the piezoelement 211 is controlled by change of the frequency of this appliedelectrical voltage. It is possible to control the conditions ofdischarge of the droplets by the discharge head 201, such as the amountof material (the mass) per one drop of the droplets, the flying offspeed of the droplets, the straightness of flying off of the droplets,and so on, by controlling the drive conditions for the piezo element(the waveform of its drive signal). In addition, the discharge head 201is supported by a head carriage 208 so as to be freely shiftable in apredetermined direction. This head carriage 208 includes a drive devicewhich is not shown in the figures, and sets the position of thedischarge head to a predetermined position, based upon commands from thecontrol device.

The stage 202 is an element for supporting the substrate P which is tobe patterned, as an object body upon which the liquid material is to bedeposited, and it includes a drive device which is not shown in thefigures which, based upon commands from the control device 205, shiftsthe substrate P in a predetermined direction. By depositing dropletsupon the substrate P repeatedly while the discharge head 201 and thesubstrate P are being shifted relatively to one another, it is possibleto deposit the liquid material in a pattern upon the substrate P. Inaddition, it is possible to form a linear pattern upon the substrate Pby depositing a plurality of droplets continuously upon the substrate Pin series during the above described relative shifting.

The measuring apparatus 204 is a device which takes advantage of thecharacteristics of a piezoelectric element (in this example, the quartzcrystal oscillator 224) to measure droplet information such as the massof a droplet which has been discharged from the discharge head 201 andthe like, and it includes a pulse generation section 220, a sensor tip221, a frequency counter 222 which serves as a detection section, acalculation section 223, and the like. The pulse generation section 220is a device which supplies a pulse signal to the sensor tip 221 andthereby causes the quartz crystal oscillator 224 to vibrate. Measurementof the droplet information is performed in order, for example, to checkthat the droplet is being discharged in a desired state, and it isperformed, for example, before depositing the liquid material from thedischarge head 201 upon the substrate p, or during the deposition of theliquid material.

Furthermore, the structure of the sensor tip 221 is the same as that ofthe sensor tip 121 shown in FIG. 2 according to the first embodiment.

Returning to FIG. 16, the sensor tip 221 is provided with an electrode225 a on its one side so as to oppose the droplet discharge surface uponthe discharge head 201. When a droplet which has been discharged fromthe discharge head 201 adheres to the electrode 225 a, the mass of thisdroplet which has adhered to the electrode 225 a is calculated by themeasuring apparatus 204. Furthermore, during this measurement, the headcarriage 208 shifts the discharge head 201 so that the droplet adheresto the surface of the electrode 225 a.

The quartz crystal oscillator 224 vibrates at a constant resonantfrequency if the external force which acts upon it is constant, but itis endowed with the characteristic that, if an object adheres to thesurface of the electrode 225 a and the external force changes, itsresonant frequency changes according to this amount of change of theexternal force. In other words, the quartz crystal oscillator 224 isendowed with the characteristic that, if an object adheres to theelectrode 225, it vibrates at a resonant frequency which corresponds tothe mass of that object. If the object which has adhered is endowed withviscoelasticity, the resonant frequency of the quartz crystal oscillator224 changes according to the viscosity of that object. Furthermore, themeasuring apparatus 204 of this example is one which is not endowed withany function of correcting errors due to the influence ofviscoelasticity; in other words, it is a device of the so calledself-excited type.

The frequency counter 222 detects the resonant frequency of the quartzcrystal oscillator 224, and supplies an oscillation which indicates theresult of this detection to the calculation section 223. Then, when thecalculation section 223 inputs this signal which has been outputted fromthe frequency counter 222 which specifies the resonant frequency, ituses it to obtain the mass of the droplet.

Furthermore, the resonant frequency change of the quartz crystaloscillator 224 which is detected by the frequency counter 222 is thesame as the change of frequency shown in FIG. 11. In addition, thecontinuation time period in the roughly steady state which is to be thestandard for detection is determined appropriately according to thecharacteristics of the measuring apparatus 204 and the measurementaccuracy which is required.

Here, the time difference <T1−T2> between the discharge time <T1> andthe adhesion time <T2> is the flying time of the droplet from when thedroplet is discharged from the discharge head 201 to when it collideswith and adheres to the sensor tip 221. Accordingly, it is possible tocalculate the speed of flying off of the droplet (its discharge speed)from the above described time difference and the distance from thedischarge head 201 to the sensor tip 221 (the electrode 225 a). In otherwords, if the above described distance is Lj, and the speed of flyingoff of the droplet is Vj, then Vj=Lj/|T1−T2|. This calculation isperformed in the calculation section 223 (refer to FIG. 16).

In addition, since the frequency <fb> after drying is one whichcorresponds to the dried layer resulting from the droplet, it ispossible to calculate the mass of the solid component of the droplet(the amount of its solid component) from the difference <fa−fb> betweenthe frequency <fa> before adhesion of the droplet and the frequency <fb>after it has dried. In other words, it is possible to calculate theamount of the solid component of the droplet by substituting the abovedescribed amount of change of the frequency into a predeterminedcalculation equation which corresponds to the characteristic of thequartz crystal oscillator 224. Although the measuring apparatus 204 ofthis example is one which is not endowed with any function of correctionfor the influence of viscoelasticity, since no result of measurementduring drying of the droplet is utilized in the above describedcalculation of the amount of the solid component, accordingly astabilized measurement result is obtained while avoiding any influenceupon the measurement due to viscoelasticity of the droplet.

In addition, the mass of the droplet which has adhered to the sensor tip221 is calculated by the calculation section 223 from the abovedescribed result of calculation of the amount of the solid component,and from the concentration of the solid component in the droplet, inother words, from the initial solid component concentration of theliquid material which is supplied to the discharge head 201. In otherwords, when the solid component concentration of the liquid material istaken as c (%), the amount of the solid component which has beenmeasured by the measuring apparatus 204 is taken as ms, and the mass ofthe droplet is taken as Im, then Im=(ms/c)×100. The mass Im of thedroplet which is calculated here is one which does not include anyinfluence due to viscoelasticity of the droplet, and has a stabilizedaccuracy. Furthermore, if no solid component is included in the liquidmaterial which is utilized, or if although some solid component isincluded the amount thereof is extremely small, then it will beacceptable to add a solid component to the liquid material in advance,within the range in which the characteristics of the liquid material donot vary greatly. In addition, before measuring the above describeddroplet information, it is beneficial to discharge a preparatory dropletfrom the discharge head 201 at a place which is different from thesensor tip 201, in order to eliminate any difference in concentrationbetween the liquid material which is supplied to the discharge head andthe droplets which have actually been discharged (this is termed“flushing”).

Now, when discharging a droplet from the discharge head 201, the targetvalue for the amount of this droplet discharge (the amount of materialin the droplet) is determined (for example at 10 ng (nanograms)), and adrive waveform which corresponds to this target value is supplied fromthe control device 205 to the discharge head 201. However, it may happenthat the actual amount of material in the droplet is different from thistarget value, due to various errors such as change of thecharacteristics of the liquid material within the discharge head 201,errors in the response characteristic of the piezo element 211, errorsin the volume of the pressure chamber 210, errors in the outer diameterof the nozzle 212, and the like. If the actual amount of material in thedroplet is different from the target value, this invites deteriorationof the accuracy of deposition of the liquid material upon the substrateP.

In addition, the above described error exerts an influence upon thespeed of flying off of the droplet as well. If the actual speed offlying off of the droplet is different from the target value, then,during deposition of the droplet upon the substrate P while shifting thedischarge head 201 and the substrate P with respect to one another, orthe like, it may happen that its collision and adhesion positiondeviates from the target position.

With the droplet discharge apparatus of this example, the informationfor the droplet which is discharged from the discharge head 201 ismeasured by the measuring apparatus 204, and, based upon the result ofthis measurement, the drive waveform which is supplied to the dischargehead 201 is set so as to bring the actual amount of material in thedroplet and the actual speed of flying off of the droplet towards theirtarget values. In other words, the control device 205 utilizes thecurrent drive waveform (the standard drive waveform) if the measurementresults of the measuring apparatus 204 fall within a certain standard.Conversely, if the above described measurement results fall outside thestandard, by changing the drive waveform, it establishes dischargeconditions (a drive waveform) which are most suitable. This optimizationof the drive waveform may be performed by, for example, storing varioustypes of droplet information in advance in correspondence with the mostsuitable drive waveforms for them, and by selecting from among thisstored data the one which conforms to the measurement results of themeasuring apparatus 204. Alternatively, the discharge of the droplet andthe measurement of the droplet information may be repeated while varyingthe drive waveform so that the various items of droplet information arebrought within the standard (feedback control). In this manner, with thedroplet discharge apparatus 200 of this example, it is possible toperform the droplet discharge in a stabilized manner at high accuracy bystriving to optimize the drive waveform for the discharge head 201 basedupon the measurement results of the measuring apparatus 204.

Furthermore, as for other examples of the resonant frequency change ofthe quartz crystal oscillator 224 which is detected by the frequencycounter 222 as well, they are the same as FIG. 12.

In addition, the drying process for the droplets in correspondence tochange of frequency is the same as the drying process shown in FIG. 13Aand FIG. 13B as well.

In this case, from the results of detection of frequency, it is possibleto calculate the speed of flying off of the droplet, the amount of thesolid component of the droplet, and the mass of the droplet, in the sameway as in the previous FIG. 11. These measurement results are ones whichdo not include any influence of viscoelasticity of the droplet, andaccordingly they have stabilized accuracy.

In addition, among the above described results of detection offrequency, it is possible to check the state of the drying process ofthe droplet from the change of frequency during the time period from theadhesion time <T6> to the time <T7> that the drying is completed (thetime period <T6−T7>). In other words, by contrast to the change offrequency along with the lapse of time with the drying time period<T2−T3> shown in the previous FIG. 11, with the drying system shown inFIG. 12, the frequency attains a roughly steady state with respect tothe lapse of time. Accordingly, it is possible to determine whethereither of the phenomena of pinning and depinning is occurring bydetecting the amount of change of the frequency during this drying timeperiod (the tendency of the graph of the change of frequency). In moreconcrete terms, for example, it is possible to decide upon pinning ifthe amount of change of the frequency in a predetermined time periodduring the drying time period exceeds a standard value, and to decideupon depinning if it is less than or equal to the standard value.

With the droplet discharge apparatus 200 of this embodiment, among thedroplet information which is measured by the measuring apparatus 204,the drying conditions for the droplet are controlled based upon theabove described information related to the drying process of thedroplet. In other words, the control device 205 checks whether or notthe drying process of the droplet, as obtained from the results ofmeasurement of the measuring apparatus 204, is in the state which isbeing aimed at; in concrete terms, which of pinning and depinning it is.Then, if it is different from the drying process which is being aimedat, the drying conditions for the droplet are controlled. This controlof the drying conditions, for example, is performed via a drying devicenot shown in the figures, such as a blower, a lamp anneal, a hot plate,an electric over, or the like. In addition, it is also possible tocontrol the drying conditions by varying the relative shifting speed ofthe droplet with respect to the atmosphere, as will be explained in thefollowing.

Furthermore, with regard to the exemplary arrangement of the sensor tip221 of the measuring apparatus 204, it may be the same as the example ofarrangement shown in FIG. 4.

Here, during the measurement of the droplet information, when thedroplet is deposited upon the sensor tip 221 (the electrode 225 a), thenthe above described stage 202 shifts in the XY plane at a predeterminedspeed. When the stage 202 shifts, the drying of the droplet is promoteddue to reduction of the vapor concentration of the vapor phase in thevicinity of the droplet and the like. The greater is the speed ofshifting of the stage 202, the greater does the relative shifting speedof the droplet with respect to the atmosphere become, so that thegreater does the drying speed of the droplet become. In addition, in thedrying process of the droplet, the greater is the drying speed at theedge of the droplet as compared with the central portion of the droplet,the easier is it for pinning to occur; while, the smaller is the dryingspeed at the edge of the droplet, the easier is it for depinning tooccur.

As a method of control of the drying conditions, for example, when ithas been checked that the actual drying process is depinning, then theshifting speed of the stage 202 is made to be greater than at thepresent time point irrespective of whether or not the drying process ofthe droplet which is being aimed at is pinning. Conversely, when it hasbeen checked that the actual drying process is pinning, then theshifting speed of the stage 202 is made to be less than at the presenttime point, irrespective of whether or not the drying process of thedroplet which is being aimed at is depinning. By doing this, it becomespossible to control the dried layer of the droplet to the desired state.

In this manner, with the droplet discharge apparatus 200 of thisembodiment, the drying conditions of the droplet are controlled basedupon the droplet information which is measured by the measuringapparatus 204, and thereby the drying state of the droplet iscontrolled. As a result, it is possible to strive to optimize the dryingconditions when depositing the liquid material upon the substrate P.

Furthermore, the sensor tip 221 and the substrate P which is to beprocessed are shifted together as one unit upon the same stage 202, andmoreover the heights of their surfaces upon which the droplets adhereare roughly equal to one another. Due to this, the difference betweenthe environmental conditions for the sensor tip 221 and the substrate Pis small, so that there is the beneficial aspect that it is possible toutilize the measurement result using the sensor tip 221 effectivelyduring the actual processing as well.

FIG. 17 is a figure showing another example of a droplet measuringapparatus (the measuring apparatus 250). Furthermore, with regard to thestructural elements of the measuring apparatus, to ones which areendowed with the same functions as those of the measuring apparatus 204previously shown in FIG. 16 the same reference symbols are appended, andtheir explanation will be curtailed or simplified.

The measuring apparatus 250 shown in FIG. 17 is different from themeasuring apparatus 204 shown previously, in that it is possible tocorrect for the influence of the viscoelasticity of the object beingmeasured, so that it is a so called external scan type device.

In FIG. 17, the measuring apparatus 250 includes a pulse generationsection 220, a sensor tip 221, a frequency counter 222, an impedancecalculation section 230, and a calculation section 231. The quartzcrystal oscillator, as previously described, along with vibrating at aresonant frequency which corresponds to the mass of the droplet, also isendowed with the characteristic that its resonant frequency changesaccording to the viscosity of this object. The measuring apparatus 250is one which takes advantage of this characteristic of the quartzcrystal oscillator, and obtains the mass and the viscosity of thedroplet. Furthermore it is possible to obtain the electrical impedanceof the quartz crystal oscillator 224 with respect to frequency from therelationship between the electrical voltage which is applied to thequartz crystal oscillator 224 and the current. This impedance changesgreatly in the vicinity of the resonant frequency. The frequency whenthe resistance component of the impedance becomes minimum is theresonant frequency, and this resistance component becomes the resonantresistance value.

The impedance calculation section 230 obtains the resonant resistancevalue of the quartz crystal oscillator 224 by calculation, and suppliesa signal which indicates this resonant resistance value to thecalculation section 231. In addition, the frequency counter 222 detectsthe resonant frequency of the quartz crystal oscillator 224, andsupplies a signal which indicates the result of this detection to thecalculation section 231. The calculation section 231 takes in thissignal which indicates the resonant resistance value which has beenoutputted from the impedance calculation section 230, and this signalwhich indicates the resonant frequency which has been outputted from thefrequency counter 222, and calculates the viscosity and the mass of thedroplet by utilizing them. In this case, the calculation is made usingEquations 1 to 3, in the same manner as explained for the impedancecalculation section 130 of the first embodiment.

Furthermore, with the measuring apparatus 250 of this embodiment, byconsidering the viscoelasticity of the droplet, in addition to the solidcomponent of the droplet, the mass of the liquid component of thedroplet may also be detected. Due to this, during the drying of thedroplet, the frequency changes according to the change of mass of thedroplet due to the evaporation of its liquid component (the solvent, thedispersion medium, or the like). In addition since, after the droplethas dried, all the liquid component has evaporated and the mass does notchange, thus the frequency attains a roughly steady state with respectto the lapse of time. Accordingly, after discharge of the droplet, it ispossible to obtain the time <T13> at which this droplet has completelydried by detecting the starting time point of the frequency being in aroughly steady state continuously for more than a predetermined timeperiod.

In addition, from the detection result for the above describedfrequency, it is possible to calculate the speed of flying off of thedroplet and the amount of the solid component of the droplet, in thesame manner as in the case of the previous FIG. 11.

In other words, if the distance from the discharge head 201 to thesensor tip 221 (the electrode 225 a) is taken as Lj, and the speed offlying off of the droplet is taken as Vj, then Vj=Lj/|T11−T12|.

In addition, since the frequency <fb> after drying is one whichcorresponds to the dried layer of the droplet, it is possible tocalculate the mass of the solid component of the droplet (the solidcomponent amount) from the difference <fa−fb> between the frequency <fa>before adhesion of the droplet and the frequency <fb> after it hasdried.

In addition, it is possible to calculate the mass of the droplet (itsdischarge amount) from the difference <fa−fc> between, among the abovedescribed results of detection of frequency, the frequency <fa> beforeadhesion of the droplet, and the frequency <fc> when the droplet hasadhered. In other words, it is possible to obtain the mass of thedroplet by substituting the difference <fa−fc> of the above describedfrequencies as the amount of change of frequency Δfreq in the Equations.In addition, in the same manner, it is possible to calculate the mass ofthe droplet at a predetermined time point during drying from thedifference <fa−fd> between the frequency <fa> before adhesion of thedroplet and the frequency <fd> at a predetermined time point (forexample, at the time <Ta>).

In this manner, it is possible to calculate the actual amount of adroplet which has been discharged from the discharge head 201, theactual speed of flying off of this droplet, and the like with themeasuring apparatus 250 of this embodiment as well. Accordingly, it ispossible to promote optimization of the drive waveform which is suppliedto the discharge head 201 which was shown in the previous FIG. 16 byusing this measuring apparatus 250.

FIGS. 18A to 18C show an example of procedures of a method for forming alinear film pattern upon a substrate, using the above described dropletdischarge apparatus 200.

With this film pattern forming method, the liquid material is dischargedfrom the discharge head 201 as droplets, and these droplets aredeposited upon the substrate P at a fixed distance apart from oneanother (pitch). Then, a linear film pattern is formed upon thesubstrate P by repeating this deposition action of the droplets.

In concrete terms, first, as shown in FIG. 18A, droplets L4 which havebeen discharged from the discharge head 201 are deposited in order uponthe substrate P with a fixed interval being left between them. In thisexample, the deposition pitch P4 of the droplets L4 is determined so asto be greater than the diameter (the radius upon collision and adhesion)of the droplets L4 directly after they have been deposited upon thesubstrate P. Due to this, the droplets L4 do not mutually contact oneanother directly after they have been deposited upon the substrate P, sothat spreading out upon the substrate P of the droplets L4 by mutualcombination together is prevented.

After the droplets L4 have been deposited upon the substrate P,according to requirements, a drying procedure is performed in order toperform elimination of their liquid component (solvent or dispersionmedium). With regard to this drying procedure, apart from employing aconventional type of heating procedure using a heating device such as,for example, a hot plate, an electric oven, a hot air blower, a lampanneal or the like, it may be performed by shifting the stage upon whichthe substrate P is carried.

Next, as shown in FIG. 18B, the above described action of deposition ofthe droplets is repeated. In other words, in the same manner as for theprevious episode shown in FIG. 18A, liquid material is discharged fromthe discharge head 201 as droplets L5, and these droplets L5 aredeposited upon the substrate P at a fixed distance apart. At this time,the amount of material in the droplets L5 (the amount of liquid materialin a single droplet) and their deposition pitch P5 are the same as forthe droplets L4 of the previous deposition episode. In addition, thepositions of deposition of the droplets L5 are shifted by just ½ of thepitch from the droplets L4 of the previous episode, so that the dropletsL5 for this episode are deposited in intermediate positions between theindividual droplets L4 of the previous episode which are deposited uponthe substrate P. By thus depositing the droplets L5 in intermediatepositions between the droplets L4, the droplets L5 become unified withthe droplets L4, so that the gaps between the individual ones of thedroplets L4 are filled up.

In addition, at this time, although the droplets L5 of this episode arein contact with the droplets L4 of the previous episode, since theliquid component in the droplets L4 of the previous episode has alreadycompletely or at least to some extent been eliminated, accordingly thetwo of them do not much combine together and spread out upon thesubstrate P. After the droplets L5 have been deposited upon thesubstrate P, in order to perform elimination of the liquid componenttherein, in the same way as in the previous episode, according torequirements, a drying procedure is performed.

By repeating the action of depositing a series of droplets in thismanner a plurality of times, the gaps between the individual dropletswhich are deposited upon the substrate P are filled in, and, as shown inFIG. 18C, a continuous linear pattern is formed upon the substrate P. Inthis case, by increasing the number of repetitions of the action ofdeposition of droplets, the droplets become laid up in series upon thesubstrate P, and the layer thickness of the linear pattern, in otherwords the height (the thickness) from the surface of the substrate P isincreased. The height (the thickness) of the linear pattern isdetermined according the desired layer thickness which is considered tobe necessary for the final film pattern, and the number of times forrepetition of the action of deposition of the above described dropletsis determined according thereto.

When forming the above described film pattern, before depositing theliquid material from the discharge head 201 upon the substrate P, orduring the deposition of the liquid material, information about thedroplets which are being discharged from the discharge head 201 ismeasured by the measuring apparatus 204 (refer to FIG. 16), and, basedupon the results of this measurement, the drive waveform which issupplied to the discharge head 201 is set so that the actual amount ofmaterial in the droplet, and the actual speed of flying off of thedroplet approach towards their target values. In addition, beforedepositing the liquid material, the drying conditions for the dropletare also optimized. By doing this, with the film pattern forming methodof this example, along with depositing droplets of the target massesexactly in the target positions upon the substrate P, also the desireddried layer is formed. Due to this, it is possible to form a filmpattern at high accuracy in a stabilized manner.

Furthermore, this method of forming a linear pattern is not limited tothe one which is shown in FIGS. 18A to 18C. For example, it is possibleto set the deposition pitch of the droplets, and the shift amount duringrepetition, and the like, as desired.

Furthermore, the droplet discharge apparatus of this embodiment issuitable for the manufacture of a liquid crystal display apparatus whichis fitted with a color filter of the type shown in FIG. 14.

In addition, it is a matter of course that it is possible to apply theabove described liquid crystal display apparatus to an electronicapparatus such as the one shown in FIG. 15.

Third Embodiment

The basic structure of the droplet discharge apparatus which is used inthis embodiment is the same as the droplet discharge apparatus shown inFIG. 2. In the following explanation, to elements which are the same asstructural elements which are shown in FIG. 2, the same referencesymbols are appended, and explanation of the same contents as in theabove described embodiment will be curtailed.

Here, the time difference <T11−T12> between the discharge time <T11> inFIG. 5 and the adhesion time <T12> is the flying time of the dropletfrom when the droplet is discharged from the discharge head to when itcollides and adheres to the sensor tip 121. Accordingly, it is possibleto calculate the speed of flying off of the droplet (its dischargespeed) from the above described time difference and the distance fromthe discharge head 101 to the sensor tip 121 (the electrode 125 a). Inother words, if the above described distance is taken as being Lj, andthe speed of flying off of the droplet is taken as being Vj, thenVj=Lj/|T11−T12|. This calculation is performed by the calculationsection 131 (refer to FIG. 2).

In addition, since the frequency <fb> after drying is one whichcorresponds to the dried layer of the droplet, accordingly it ispossible to calculate the mass of the solid component of the droplet(the solid component amount) from the difference <fa−fb> between thefrequency <fa> before adhesion of the droplet and the frequency <fb>after it has dried.

In addition, it is possible to calculate the mass of the droplet (itsdischarge amount) from the difference <fa−fc> between, among the abovedescribed results of detection of frequency, the frequency <fa> beforeadhesion of the droplet, and the frequency <fc> when the dropletadheres. In other words, if the above described difference of frequency<fa−fc> is taken as being the amount of change of frequency Δfreq, it ispossible to obtain the mass of the droplet by substituting it in saidEquations. In addition, in the same manner, it is possible to calculatethe mass of the droplet at a predetermined time point during its dryingfrom the difference <fa−fd> between the frequency <fa> before adhesionof the droplet, and the frequency <fd> at the predetermined time point(for example, at the time <Ta>).

In addition, the solid component concentration of the droplet which hasadhered to the sensor tip 121 is calculated from the calculation resultof the solid component amount and the calculation result of the mass ofthe droplet which have been described above.

In other words, when the mass of the droplet which has been measured bythe measuring apparatus 150 is taken as being Im, the solid componentamount which is measured by the measuring apparatus 150 is taken asbeing ms, and the solid component concentration of the droplet is takenas being c, then c=Im/ms.

By the way, the diameter of the nozzle 112 (refer to FIG. 2) which isused in the discharge head 101 for droplet discharge is extremely small,and, if drying of the liquid material proceeds within the nozzle 112, itis easy for blocking thereof to occur. In other words, by the solidcomponent concentration of the liquid material within the nozzle 112mounting, there is a possibility of the solid component which isincluded in the liquid material solidifying or condensing within thenozzle 112, and of the nozzle 112 being thereby closed off.

In this embodiment, a decision is made as to the drying state of thenozzle 112 based upon the droplet information which is obtained from themeasuring apparatus 150, and blocking of the nozzle 112 is prevented inadvance.

In the following, an example of processing for preventing blocking ofthe nozzle 112 in advance will be explained with reference to the flowchart of FIG. 19.

As described above, the measuring apparatus 150 measures (in a step 101)the droplet information of the droplet which has been discharged fromthe discharge head 101. The control device 105 compares together (in astep 102), among the measurement results of the measuring apparatus 150,the solid component concentration of the droplet, and the initial solidcomponent concentration of the liquid material which is supplied to thedischarge head 101. Then, (in a step 103) a decision is made as to whatextent the liquid material within the nozzle 112 has dried.

In concrete terms, the initial solid component concentration of theliquid material is inputted in advance into the control device 105, andthe control device 105 makes a decision as to whether or not theproportion of this solid component concentration of the droplet withrespect to the initial solid component concentration is greater than astandard value. For example, if the above described proportion exceedsthe standard value (for example 120%), then it is decided that thedrying state of the nozzle 112 is progressing, while if it is less thanthe standard value, then it is decided that the drying state of thenozzle 112 is not progressing. Then, if it is decided that the dryingstate of the nozzle 112 is progressing, then the control device 105controls the drive conditions of the discharge head 101 (in a step 104),and aims to prevent blocking of the nozzle 112 in advance.

Prevention of blocking in advance, for example, is performed by stirringthe liquid material within the nozzle 112 (meniscus shaking), or byperforming preliminary droplet discharge from the nozzle 112 upon aplace which is different from the sensor tip 121 (preliminary discharge,or flushing). Or it may be performed by varying the conditions forimplementing the above described meniscus shaking or the above describedpreliminary discharge.

Here, FIG. 20 shows an example of a drive signal which is supplied to apiezo element.

In FIG. 20, the drive waveform <A> is the basic waveform which iscreated by the drive signal generation circuit. <Part 1> of thiswaveform is used for diffusing the liquid in the vicinity of the nozzleopening whose viscosity has increased by shaking the meniscus (theconcave and convex surface of the liquid within the nozzle), and forthus preventing poor discharge of the minute droplets in advance of itshappening. Then, <B1> is the state in which the meniscus is smooth andstable, while <B2> shows an action for expanding the volume of thepressure chamber (of the liquid chamber) by gently supplying electricityto the piezo element, thus pulling the meniscus a little into thenozzle.

In the step 104 of FIG. 19, the control device 105, for example,supplies the drive waveform described above for shaking the meniscus tothe discharge head 101. In addition, if a drive waveform for shaking themeniscus is already being supplied to the discharge head 101, itincreases the amplitude of this drive waveform, and/or shortens itsperiod. By doing this, stirring of the liquid material within the nozzle112 is promoted, so that it is possible to prevent blocking of thenozzle 112 in advance.

In addition if, in the step 103 of FIG. 19, it is decided that thedrying of the nozzle 112 is not progressing, then the control device 105establishes a correspondence between the solid component concentrationof the droplet which has been measured by the measuring apparatus 150,and the time which has elapsed from the time of discharging the previousdroplet, and temporarily stores this in an internal memory (in a step105). By accumulating this data, it becomes possible to grasp the stateof affairs with regard to the changes of concentration of the liquidmaterial within the nozzle 112 with respect to lapse of time; forexample, to obtain the time period from the discharge of a droplet untilthe nozzle 112 dries. As a result, it becomes possible to obtain thetime period over which it is possible to leave the nozzle 112 (thedischarge head 101) alone (the permissible waiting time), and the mostsuitable timing for performing nozzle blocking prevention processing inadvance (meniscus shaking or preliminary discharge or the like).

In this manner, with the droplet discharge apparatus 100 of thisexample, it is possible to detect the drying state of the nozzle 112 ata state before blocking of the nozzle 112 has actually occurred, and,because blocking of the nozzle 112 is prevented in advance based uponthe result of this detection, it becomes possible to preventdeterioration of the productivity which accompanies blocking of thenozzle 112. Furthermore, since increase of the concentration of theliquid material within the nozzle 112 is a cause of error in thedischarge amount of material in the droplets and in the speed of flyingoff of the droplets, accordingly it would also be acceptable to controlthe drive conditions of the discharge head 101 so as to keep the solidcomponent concentration of the droplets which is measured by themeasuring apparatus 150 to be always roughly constant. By doing this, inaddition to preventing blocking in advance, it also becomes possible toperform the droplet discharge in a stabilized manner at high accuracy.

Furthermore the droplet discharge apparatus of this embodiment canappropriately manufacture a liquid crystal display apparatus which isequipped with a color filter such as that shown in FIG. 14.

In addition, it is a matter of course that it is possible to apply theabove described liquid crystal display apparatus to an electronicapparatus such as the one which is shown in FIG. 15.

Furthermore, the application of the droplet discharge apparatus is notlimited to patterning of a color filter which is used in anelectro-optical apparatus, as in the above described embodiment; it ispossible to use it in the manufacture of various types of film pattern,as in the following. For example, it can be utilized in the formation ofa thin film for an organic EL layer or a positive hole injection layeror the like which is included in an organic EL (electroluminescence)display panel. If it is used in the manufacture of such an organic ELlayer, then droplets which include an organic EL material such as, forexample, a polythiophen type electrically conductive high molecularweight material or the like, are discharged against regions which aredelimited by division walls which are formed upon a substrate, so thatthe droplets are deposited in these regions. Then, an organic EL layeris formed by drying the liquid material which has been deposited in thismanner.

In addition, as other applications of this droplet discharge apparatus,there is the manufacture of auxiliary wiring for a transparent electrodewhich is included in a plasma display, or of a device such as an antennaor the like which is included in an IC (an integrated circuit) card orthe like. In concrete terms, after, using this droplet dischargeapparatus, patterning with a solution which is a mixture of minuteelectrically conductive particles such as minute particles of silver orthe like in an organic solution such as tetradecane or the like, thethin metallic layer is formed when the organic solution is dried.

Moreover, apart from the cases described above, this droplet dischargeapparatus may also be utilized, for example, for depositing varioustypes of material such as, apart from a thermosetting resin which isused in manufacturing solid objects, or an ultraviolet setting resin orthe like, also a micro lens array material or a bio-material such as DNA(deoxyribonucleic acid) or a protein or the like.

In addition, as an electronic apparatus, apart from a portabletelephone, there may be suggested a computer, or a projector, a digitalcamera, a movie camera, a PDA (Personal Digital Assistant), a vehiclemounted device, a copy machine, an audio device, or the like.

While preferred embodiments of the invention have been described andillustrated above, furthermore these are exemplary of the invention andare not to be considered as limiting. Additions, omissions,substitutions, and other modifications can be made without departingfrom the spirit or scope of the present invention. Accordingly, theinvention is not to be considered as being limited by the foregoingdescription, and is only limited by the scope of the appended claims.

1. A droplet discharge apparatus comprising: a discharge head thatdischarges a droplet; a droplet information measuring apparatus thatmeasures information of the discharged droplet; and a control devicethat controls the discharge head, wherein: the droplet informationmeasuring apparatus includes: an oscillator that has a surface receivingthe discharged droplet; a detection section that detects a frequency ofthe oscillator; and a calculation section that calculates a mass of thedischarged droplet, the control device controls the discharge head basedon a first frequency and a second frequency, the first frequency being afirst oscillating frequency of the oscillator when the surface does notreceive the discharged droplet, and the second frequency being a secondoscillating frequency of the oscillator when the discharged droplet hasdried on the surface, the discharged droplet includes a solid componentand a liquid component, and the solid component in the dischargeddroplet remains on the surface when the discharged droplet has dried onthe surface, the calculation section calculates a mass of the solidcomponent in the discharged droplet and further calculates aconcentration of the solid component in the discharged droplet, liquidmaterial is provided to the discharge head as a source of the dischargeddroplet, an initial concentration of the solid component of the liquidmaterial is input to the control device, the control device compares thesolid component in the discharged droplet and a standard value of thesolid component of the liquid material, the standard value is based onthe initial concentration of the solid component of the liquid material,and the control device controls the discharge head based on thecomparison result so as to prevent blocking of a nozzle.
 2. The dropletdischarge apparatus according to claim 1, wherein the surface is asurface of an electrode.